Connecting separated edges
Try using remove doubles in the tool shelf (T) while having the part selected where the edges are separated. You can increase the merge distance beneath the tool shelf. If this doesn't give you what you want you can do it manually by zooming in to the edge that you want to correct in vertex select mode and selecting the two separated vertices. Then press Alt M and choose the option that's the best for you, probably at center. 

Side note: Please make clearer question titles. 'Question about Sculpt Mode' is pretty general and nobody really knows what your question is about. Something like e. g. 'Connecting separated edges' would be better. Keep that in mind.